This section provides background information related to the present disclosure that is not necessarily prior art.
In certain orthopedic procedures, it can be necessary to secure multiple bones or bone portions relative to each other to facilitate proper healing. For example, it is frequently necessary to secure two or more portions of a broken long bone to ensure proper healing. This need may be the result of physical trauma from fractures or dislocations, degenerative diseases, or tumors.
Common methods of fracture treatment include casting and external fixation. It is also known to treat fractures with internal plating systems. Use of such plating systems involves the attachment of a plate to the bone with bone screws. The plating systems function to stabilize discrete bone portions and thereby facilitate fusion of the bone portions in a particular orientation for healing or to repair a condition of the patient.
Plating systems that use locking screws are generally known. One known plating system is shown in German Patent Application No. DE 43 43 117. This German application illustrates a bone plate with threaded holes for locking screws with externally threaded heads. The locking screw is inserted coaxially with the threaded hole in the bone plate.
It may also be desirable for a surgeon to be able to insert a locking bone screw through a bone plate hole at a selected angle to the bone plate. Various bone plate systems having such “polyaxial” capability are also generally known. These known systems, however, typically employ a bushing or expandable ring that is movable within the bone plate hole. As the bone screw is threaded into the bone through the bushing or ring, the head of the bone screw expands the bushing or ring against the bone plate hole wall thereby friction locking the bone screw at the desired angle. Such polyaxial bone plate systems, however, can be difficult to manipulate during surgery, as well as require an additional component (i.e., bushing or ring) to facilitate the polyaxial capability which increases the complexity of the system.
Thus, while polyaxial bone plate systems have generally worked for their intended purpose, there remains a need for continuous improvement in the relevant art.